Based on extensive experience as a reviewer of evaluations of federal
health programs, the author distinguishes and discusses two sources of
evidence for the credibility of cui evaluation, Substantive credibili
ty is indicated by the quality of the literature review; the evaluativ
e understanding manifest in the description of the program or treatmen
t; the relation between the study questions and the study design; the
expertise and candor display in the methods discussion; and the degree
to which stated findings and recommendations are supported by methods
and data. Presentational credibility is undermined by language that r
eveals subjectivity or advocacy, but it is supported by the competent
organization and readability of the report.